Left/Right Tune

my robot pulls a little to the left. I'm using 2 npc T74s in mixed mode. I go to program # 10 (or L on controller readout). Select gives me 0,1,2,3. I press program again, I get O for program then the 0,1,2,3,4,5,6,7,8,9,A,b,C,d,E (which is what I'm looking for)But in the manual, I see no explanation of the Prog.-L Select 0,1,2,3 and there seems to be no different effect when any one is chosen. Can you help me?

The left/right adjust function is designed to correct the fact that many motors are timed to work more efficiently in one direction than the other. This can be a problem in mixed mode trying to go staight: with the same amount of power applied one motor will run faster that the other and the robot will tend to turn.

At default, the controller's setting is "centered" meaning that the same amount of power is applied to both motors. The setting can be changed to create a difference of up to about +/-10 difference between the two sides.

This setting can be changed either using the PC utility or the built-in switches.

With the PC utility, all you need to do is move the slider and save the settings to the controller. The PC utility has the added benefit that you can see the correction at work in the "run" menu: as you change the throttle, you can see on the graph that one side does get more power than the other.

The switches are a more convenient ways to change that setting. Move to the letter "L". The default setting is "7" (centered). Moving further from that number in each direction increases the correction in that direction (0= max correction in one directio, F = max correction in the other). It looks like you have gotten that far. Make sure that you press the "Prog" button again after you have selected the new value for it to get stored in the controller's flash.

If you do not observe a change, I suggest that you use the PC with Roborun utility to do your test. This method gives you much more visibility into what's going on and we might be able to help you better.

Thanks Cosma, I understand what you are saying. Thats the same info as in the manual. But you didn't explain why at Program L you may select: 0,1,2,3. Now you press program, you see 0 and then you may select 0,1,2,...A,b..E of which 7 is default of course. So here's what you have
Program: L Select: 0,1,2,3
Program: O Select: 0,1,2,3,4,5,6,7,8,9,A,b,C,d,E

The second part is no problem. What is the meaning of the first part P:L S:0,1,2,3
Thanks again